Note: Descriptions are shown in the official language in which they were submitted.
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GAS PRESSURE CONTROL APPARATUS
Field of the Invention
The present invention relates to regulators for providing relatively low
pressure flows of gas from high pressure sources.
Background of the Invention
A pressurized gas may be stored in a cylinder having an outlet valve. The
valve can be opened manually to release the stored gas to exit the cylinder at
flow rates that
correspond to the storage pressure in the cylinder. For example, pressurized
oxygen for
home health care may be stored in an aluminum cylinder having such an outlet
valve. When
the oxygen is to be released from the cylinder, a pressure-reducing regulator
is first mounted
on the outlet valve so that the oxygen must pass through the regulator before
it is accessible
for breathing. The operator then opens the outlet valve on the cylinder, and
the oxygen
emerges from the regulator at a pressure that is greatly reduced from the
storage pressure in
the cylinder.
The regulator has a high pressure gas flow passage which receives the
oxygen directly from the outlet valve on the cylinder. The high pressure
passage conveys the
oxygen to a spring-biased piston which operates to limit the pressure of the
oxygen emerging
from the regulator. Before the oxygen reaches the piston, it flows through
portions of the
high pressure passage that constrict toward a control orifice. Accordingly,
the oxygen
flowing through the regulator undergoes at least partially isothermal
compression in the high
pressure passage. A corresponding amount of heat is then absorbed and
disipated by the
structure of the regulator. For this reason known regulators are formed
predominately of
brass or other metal materials that can withstand internal temperatures such
as, for example,
1800° F or more.
Summary of the Invention
In accordance with the present invention, a gas pressure control apparatus
has a high pressure inlet port and low pressure outlet port. A spring-biased
piston is
operatively interposed between the inlet and outlet ports. The apparatus
includes a metal part
with a high pressure passage communicating the inlet port with the piston. The
high
pressure passage has a portion with a relatively constricted flow area,
whereby compression
of gas flowing through the passage yields heat of compression that heats the
metal part. The
apparatus further includes a plastic part configured to engage and support the
metal part in
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an operative position in which the inlet port communicates
with an outlet port on a pressure vessel outlet valve.
In a preferred embodiment of the present
invention, the plastic part of the apparatus defines a yoke
which is receivable over a post valve on a pressure vessel.
In another preferred embodiment, the plastic part has a
screw-threaded sleeve portion engageable coaxially with a
corresponding screw-threaded stem portion of an outlet valve
on a pressure vessel.
In one broad aspect, the invention provides an
apparatus comprising: a gas pressure control apparatus
defining a high pressure inlet port, a low pressure outlet
port, and a spring-biased piston operatively interposed
between said inlet port and said outlet port; said gas
pressure control apparatus including a metal part having a
high pressure passage communicating said inlet port with
said piston, said high pressure passage having a portion
with a relatively constricted flow area, whereby compression
of gas flowing through said high pressure passage yields
heat of compression that heats said metal part; said gas
pressure control apparatus further including a plastic part
configured to engage and support said metal part in an
operative position in which said inlet port communicates
with an outlet port on a pressure vessel outlet valve.
In one broad aspect, the invention provides an
apparatus comprising: a gas pressure control apparatus
defining a valve structure and a mounting structure; said
mounting structure including a yoke configured to extend
around a pressure vessel outlet valve; said valve structure
having a high pressure inlet port, a low pressure outlet
port, a spring-biased piston operatively interposed between
said inlet outlet ports, and a flow rate selector assembly
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operatively interposed between said piston and said outlet
port; said gas pressure control apparatus including an
outlet part having a low pressure passage communicating said
piston with said outlet port, a metal inlet part having a
high pressure passage communicating said inlet port with
said piston, and a plastic supporting part defining said
yoke.
In one broad aspect, the invention provides an
apparatus comprising: a plastic part defining a cylindrical
compartment with a longitudinal central axis, said plastic
part further defining a yoke configured to receive a
pressure vessel post valve perpendicular to said axis, said
yoke comprising a U-shaped structure having a pair of
axially elongated side sections joined by a base section
extending across said axis; and a cylindrical metal valve
body received in said compartment, said valve body having an
inlet port, a control orifice, and a high pressure gas
passage extending from said inlet port to said control
orifice; said plastic part having an annular end surface
defining an open end of said compartment, a cylindrical
inner surface mating with a cylindrical peripheral surface
of said valve body within said compartment, and a pair of
planar inner surfaces which face axially outward of said
open end of said compartment in abutment with a planar
surface of said valve body, with said planar inner surfaces
being defined by said side sections of said yoke.
In one broad aspect, the invention provides an
apparatus comprising: a gas pressure control apparatus
including parts which together define a valve structure and
a mounting structure; said mounting structure including a
yoke configured to extend around a pressure vessel outlet
valve; said valve structure having a high pressure inlet
port, a low pressure outlet port, a spring-biased piston
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operatively interposed between said inlet outlet ports, and
a flow rate selector assembly operatively interposed between
said piston and said outlet port; said parts including an
outlet part having a low pressure passage communicating said
piston with said outlet port, a metal inlet part having a
high pressure passage communicating said inlet port with
said piston, and a supporting part defining said yoke; said
metal inlet part further having a branch passage extending
from said high pressure passage to an outer surface of said
metal inlet part, with said branch passage being configured
to receive a stem portion of a gas pressure gauge.
In one broad aspect, the invention provides an
apparatus comprising: a gas pressure control apparatus
defining a high pressure inlet port, a low pressure outlet
port, and a spring-biased piston operatively interposed
between said inlet port and said outlet port; said gas
pressure control apparatus including a metal part having a
high pressure passage communicating said inlet port with
said piston, said high pressure passage having a portion
with a relatively constricted flow area, whereby compression
of gas flowing through said high pressure passage yields
heat of compression that heats said metal part; said gas
pressure control apparatus further including a supporting
part configured to engage and support said metal part in an
operative position in which said inlet port communicates
with an outlet port on a pressure vessel outlet valve; said
gas pressure control apparatus further defining a gas flow
path configured to direct gas to flow from said high
pressure passage into a gas pressure gauge without
contacting a surface of said supporting part.
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In one broad aspect, the invention provides an
apparatus comprising: a gas pressure control apparatus
defining a high pressure inlet port, a low pressure outlet
port, and a spring-biased piston operatively interposed
between said inlet port and said outlet port; said gas
pressure control apparatus including a metal part having a
high pressure passage communicating said inlet port with
said piston, said high pressure passage having a portion
with a relatively constricted flow area, whereby compression
of gas flowing through said high pressure passage yields
heat of compression that heats said metal part; said gas
pressure control apparatus further including a supporting
part configured to engage and support said metal part in an
operative position in which said inlet port communicates
with an outlet port on a pressure vessel outlet valve; said
metal part further having a branch passage extending from
said high pressure passage to an outer surface of said metal
part, with said branch passage being configured to receive a
stem portion of a gas pressure gauge.
Brief Description of the Drawings
The foregoing and other features of the present
invention will be apparent to those skilled in the art upon
reading the following description in view of the
accompanying drawings, wherein:
Fig. 1 is an exploded view of an apparatus
comprising a first embodiment of the invention;
Fig. 2 is a sectional view showing parts of the
apparatus of Fig. 1 in an interconnected relationship;
Fig. 3 is a sectional view of a part shown in
Fig. 2;
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Fig. 4 is a view taken on line 4-4 of Fig. 3;
Fig. 5 is a view taken on line 5-5 of Fig. 3;
Fig. 6 is an enlarged partial view of parts of an
apparatus comprising a second embodiment of the invention.
Fig. 7 is an exploded view of an apparatus
comprising a third embodiment of the invention;
Fig. 8 is an enlarged partial view of parts of an
apparatus comprising a fourth embodiment of the invention;
and
Fig. 9 is a sectional view of an apparatus
comprising a fifth embodiment of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
An apparatus 10 comprising a first embodiment of
the present invention is shown partially in Fig. 1. The
apparatus 10 includes a pressure vessel 12 and a
regulator 14. The pressure vessel 12 in the first
embodiment is an aluminum cylinder with a storage chamber 15
containing pressurized oxygen 16. An outlet valve 18 is
mounted on the upper end of the cylinder 12. The outlet
valve 18 in the first embodiment is a post valve with a gas
outlet port 20, and includes a wing knob 22 for releasing
the oxygen 16 to flow from the
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storage chamber 15 to the outlet port 20. Also shown in Fig. 1 is a barb
outlet 24 for
engaging an oxygen supply hose 26 that extends to an oxygen mask or the like.
The
regulator 14 is receivable over the post valve 18 in an operative position in
which the
regulator 14 communicates the outlet port 20 with the barb outlet 24. The
regulator 14 then
functions to provide an outlet flow of oxygen 16 at a pressure that is greatly
reduced from the
storage pressure in the chamber 15. Additionally, the regulator 14 in this
embodiment
includes a flow rate selector 26 for providing predetermined outlet flow
rates.
The regulator 14 is an elongated device with a longitudinal central axis 29,
and has a valve portion 30 and a mounting portion 32, each of which extends
about one-half
the length of the regulator 14. The mounting portion 32 of the regulator 14
includes a yoke
34 and a T-handle 36. The yoke 34 is a generally U-shaped structure with a
pair of axially
elongated side sections 38 (Fig. 2) and a transversely extending base section
40. A pair of
opposed, planar inner surfaces 42 of the side sections 38 are configured to
engage
corresponding opposite side surfaces 46 of the post valve 18 when the yoke 34
is received
over the post valve 18, as shown in Fig. 2. An inlet stub 48 on the valve
portion 30 of the
regulator 14 is then received closely within the outlet port 20 on the post
valve 18. A pair of
alignment pins 50 projecting from the valve portion 30 of the regulator 14 are
similarly
received in a corresponding pair of alignment openings 52 (Fig. 1) in the post
valve 18.
As further shown in Fig. 2, the base section 40 of the yoke 34 has a screw-
threaded tubular insert 54. The insert 54 supports a shaft portion 56 of the T-
handle 36 for
movement along the axis 29 upon manual rotation of the T-handle 36 about the
axis 29. A
conical recess 58 on a rear surface 60 of the post valve 18 receives a conical
end portion 62 of
the shaft 56 when the T-handle 36 is advanced and tightened axially against
the past valve
18. A planar front surface 64 of the post valve 18 then mates firmly with an
opposed, planar
rear surface 66 of the valve portion 30 of the regulator 14. Firm abutting
contact between the
opposed planar surfaces 64 and 66, as well as a close fit of the inlet stub 48
in the outlet port
20, helps to ensure that the oxygen 16 emerging from the post valve 18 does
not escape
through the yoke 34.
The valve portion 30 of the regulator 14 includes a metal body 70. The
metal body 70 defines the inlet stub 48 and the planar rear surface 66 which
surrounds the
stub 48. The metal body 70 further has a cylindrical outer surface 72 and a
planar, annular
front surface 74 centered on the axis 29. A conical portion 76 of the metal
body 70 projects
longitudinally from the front surface 74 and also is centered on the axis 29.
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A cylindrical bore 78 in the metal body 70 extends
axially inward from the outer end of the conical
projection 76. A high pressure gas passage 80 extends
axially inward of the metal body 70 in the opposite
direction from the inlet stub 48 toward the bore 78. More
specifically, the high pressure passage 80 includes an inlet
port 82 at the stub 48, and further includes a control
orifice 84 at the bore 78. A branch passage 86 in the metal
body 70 extends radially from the high pressure passage 80
to the cylindrical outer surface 72. The branch passage 86
has a screw-threaded outer end portion 88 for receiving a
corresponding stem on a gas pressure gauge (not shown).
In accordance with a principal feature of some
embodiments of the present invention, the metal body 70 is
contained and supported by a plastic part 100 of the
regulator 14. The plastic part 100 defines the yoke 34 and,
as shown separately in Figs. 3-5, has a cylindrical
compartment 102 for containing the metal body 70. The
diameter of the compartment 102 is defined by a cylindrical
inner surface 104 of the plastic part 100. The cylindrical
inner surface 104, in turn, is defined by a cylindrical wall
portion 106 of the plastic part 100 that extends axially
from the yoke 34 to the opposite end of the plastic
part 100. The compartment 102 thus has an outer end 108
defined by an annular edge surface 110 of the cylindrical
wall 106. An inner end 112 of the compartment 102 is
defined in part by planar end surfaces 114 of the side
sections 38 of the yoke 34, and in part by arcuate edge
surfaces 116 of the cylindrical wall 106 that extend
circumferentially between the side section 38 of the
yoke 34. An external screw thread 117 on the cylindrical
wall 106 extends axially from the edge surface 110. An
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access opening 118 for the pressure gauge extends radially
through the cylindrical wall 106.
The plastic part 100 could be formed separately
from the metal body 70. The metal body 70 would then be
received through the outer end 108 of the compartment 102
and moved axially inward until the planar rear surface 66 on
the metal part 70 abuts the planar surfaces 114 on the
yoke 34. The cylindrical inner and outer surfaces 104
and 72 would preferably establish an interference fit to
interlock the metal body 70 and the plastic part 100.
However, the plastic part 100 is preferably formed around
the metal body 70 in an insert molding process to establish
a more secure interlock. For example, the cylindrical inner
and outer surfaces 104 and 72 in the first embodiment of the
invention are tapered slightly so as to block movement of
the metal body 70 axially outward of the compartment 102.
Other interlocking arrangements can be used, as described
below with reference to the second embodiment of the
invention. Moreover, the plastic part 100 preferably is a
one-piece
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structure made from a single homogenous material. By "one-piece" it is meant
that the
plastic part 100 is a single unit exclusive of separate but joined elements.
The plastic
material may include additives such as stabilizers, fillers, reinforcements,
and the like.
The valve portion 30 of the regulator 14 further includes a
piston/diaphragm assembly 130 and a generally cylindrical part which is known
as bonnet
132. The bonnet 132 in the first embodiment also is formed of plastic, and is
interconnected
with the other plastic part 100 by a nut 134 which is screwed onto the
cylindrical wall 106.
The piston/diaphragm assembly 130 includes a piston 136 and a diaphragm 138.
The piston
136 is mounted on the diaphragm 138 by a pair retainer rings 140. A spring 142
is engaged
compressively between a retainer ring 140 and the planar front surface 74 of
the metal body
70 so as to bias the piston/diaphragm assembly 130 axially away from the metal
body 70, i.e.
from left to right as viewed in Fig. 2. A peripheral portion 144 of the
diaphragm 136 is
clamped between the annular edge surface 110 of the plastic part 100 and an
opposed
annular edge surface 146 of the bonnet 132. In this arrangement, a pair of
variable volume
gas pressure chambers 150 and 152 are defined within the valve portion 30 of
the regulator
14 on opposite sides of the piston/diaphragm assembly 130.
A vent opening 154 communicates the first pressure chamber 150 with the
ambient atmosphere. A low pressure passage 156 in the bonnet 132 communicates
the
second pressure chamber 152 with an outlet port 158. The bonnet 132 has an
internal screw
thread 160 adjacent to the outlet port 158 for receiving an external screw
thread 162 on the
barb outlet 24 (Fig. 1).
The flow rate selector 26 includes a circular orifice plate 170. A
circumferentially extending array of outlet orifices 172, each of which has a
unique size,
extends axially through the orifice plate 170. The orifice plate 170 is
mounted on a manually
rotatable knob 174 such that each orifice 172 can be moved into alignment with
the low
pressure passage x.56 upon rotation of the knob 174 about the axis 29. A ball
detent
mechanism 176 operates between the orifice plate 170 and the bonnet 132 to
retain a selected
orifice 172 releaseably in alignment with the low pressure passage 156.
In operation of the apparatus 10 (Fig. 1), the oxygen 16 flowing through
the post valve 18 enters the high pressure passage 80 in the metal body 70
through the inlet
port 82. The oxygen 16 then flows from the high pressure passage 80 to the
bore 78 through
the control orifice 84, and further from the bore 78 to the second gas
pressure chamber 152
through a passage 188 in the piston 136. As the gas pressure in the second
chamber 152
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increases, the pressure force acting on the piston/diaphragm assembly 130 in
the second
chamber 152 increases to a specified level that exceeds the combined forces of
the spring 142
and the pressure acting against the free end of the piston 136 at the control
orifice 84. The
piston/diaphragm assembly 130 is then shifted to the left to a position in
which the free end
of the piston 138 blocks the control orifice 84, as shown in Fig. 2. The
pressure at the
control orifice 84 moves the piston/diaphragm assembly 130 back to the right
as the oxygen
16 is vented from the second chamber 152 through the orifice plate 170 and the
low pressure
passage 156. This repeats continuously during operation of the apparatus 10 so
that the gas
pressure in the second chamber 152 cannot exceed the specified level. For
example, the
specified level of gas pressure in the first embodiment of the invention is
within a range of
about 20 psi to about 50 psi, whereas the storage pressure in the chamber 15
(Fig. 1) is about
2,200 psi. The operator of the apparatus 10 can then use the selector 26 to
vary the outlet
flow rate among the values that result from the differing flow areas at the
orifices 172.
As further shown in Fig. 2, the high pressure passage 80 in the metal body
70 has axially successive constricted portions leading to the control orifice
84. When the
oxygen 16 flows through the regulator 14 in the foregoing manner, it is
constrained to
undergo at least partially isothermal compression in those portions of the
high pressure
passage 80. The resulting heat of compression heats the metal body 70. In
accordance with
the present invention, the surrounding wall portion 106 of the plastic part
100 extends axially
over the metal body 70, but is configured as a thin-walled cylinder and is
thus spaced from
the high pressure passage 80 by the radially extending mass of the metal body
70. This
configuration enables the plastic part 100 to engage and support the metal
body 70 while
simultaneously being insulated from the heat of compression by the metal body
70. The open
cylindrical configuration of the wall 106 further enables radiation and
convection of heat
from the conical projection 76 and the front surface 74 of the metal body 72
in the second
chamber 152. Additionally, the planar surfaces 114 on the side sections 38 of
the yoke 34
abut the rear surface 66 of the metal body 70 at locations that are spaced
radially from the
high pressure passage 80 so that the heat of compression can be conducted from
the rear
surface 66 to the post valve 18 before reaching the yoke 34.
As noted above, a metal valve body and a plastic supporting part can be
interlocked in accordance with the present invention in arrangements other
than the tapered
arrangement of the metal body 70 and the plastic part 100. For example, as
shown partially
in Fig. 6, a second embodiment of the invention includes an alternative metal
valve body 200
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and a corresponding alternative plastic supporting part 202. The metal body
200 and the
plastic part 202 have mating cylindrical surfaces 204 and 206 with undulating
contours
defined by helically extending splines 208 on the cylindrical surface 204 of
the metal body
200. The splines 208 inpart an oppositely undulating contour to the mating
cylindrical
surface 206 upon formation of the plastic part 202 around the metal body 200
in an insert
molding process. The metal body 200 and the plastic part 202 are otherwise
substantially the
same as the metal body 70 and the plastic part 100 described above.
An alternative regulator 300 comprising a third embodiment of the present
invention is shown in Fig. 7. The regulator 300 has many parts that are
substantially the
same as corresponding parts of the regulator 14 described above. This is
indicated by the use
of the same reference numbers for such corresponding parts in Figs. 2 and 7.
The regulator
300 thus includes a flow rate selector 26, a spring biased piston/cylinder
assembly 130, and a
plastic bonnet 132. However, the regulator 300 includes an alternative metal
valve body 302
contained and supported by an alternative plastic part 304.
Unlike the metal body 70 described above, which defines an inlet stub 48
receivable in an outlet port 20 in a post valve 18, the metal body 302 has a
separate inlet
nipple 306 receivable in a screw-threaded cylinder valve outlet 308. The valve
outlet 308 is a
known part which. ~s mounted on an oxygen cylinder 310 (shown schematically)
in a known
manner. The plastic part 304 of the regulator 300 likewise differs from the
plastic part 100
of the regulator 14 by including an alternative mounting structure 312 in
place of the yoke
34. The mounting structure 312 on the plastic part 304 is configured as an
internally
threaded sleeve receivable over the valve outlet 308 upon rotation of the
regulator 300 about
its longitudinal central axis 315. In a variation of this feature of the
invention, a fourth
embodiment includes a plastic part 400 with an externally thread mounting
sleeve 402
receivable in an internally threaded nut portion 404 of a cylinder valve
outlet, as shown
partially in Fig. 8.
A regulator 500 comprising a fifth embodiment of the present invention is
shown in Fig. 9. This regulator 500 has a metal valve body 502 defining an
inlet port 504, a
plastic part 506 defining an outlet port 508, and a spring biased piston 510
operatively
interposed between the inlet and outlet ports 504 and 508. The metal body 502
has a high
pressure passage 512 communicating the inlet port 504 with a control orifice
514. These
parts of the regulator 500 function in a known matter substantially similar to
that described
above with referer~~e to corresponding parts of the regulator 14. The
regulator 500 further
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includes a spring-biased outlet pressure indicator 516 which also functions in
a known
matter.
In accordance with the present invention, the regulator 500 includes a one-
piece plastic part 520 in which the metal body 502 is received and supported
for mounting on
a pressure vessel outlet valve. Specifically, the plastic part 520 and the
metal body 502 have
mating inner and outer cylindrical surfaces 522 and 524, respectively, which
are tapered or
otherwise configured to interlock the metal body 502 with the plastic part
520. A sleeve
portion 526 of the plastic part 520 has an external screw thread 528 for
engagement with an
internal screw thread on a part like the part 404 shown in Fig. 8.
The invention has been described with reference to preferred embodiments.
Those skilled in the art will perceive improvements, changes and
modifications. Such
improvements, changes and modifications are intended to be covered by the
appended
claims.
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